When the news broke last week that West Mercia police force has spent £200,000 on an American motivational guru to train 999 call staff to stop using the words 'can't' and 'unfortunately', it sounded like a bad sketch from The Two Ronnies. Critics were incensed by this apparent waste of taxpayers' money, claiming the force could have an extra four officers on the beat for £200,000.

But the woman behind the scheme, guru Mary Gober (or 'Mrs Motivator' as the tabloids love to call her) is no joke. She specialises in persuading those who serve the public not just to deliver better service, but to want to do so. Having happy, motivated customer assistants leads to good customer service, she argues.

Gober, 56, is the latest big idea for human resources directors seeking 'culture change' among their staff. Companies who have been 'Goberised' include Marks & Spencer, Nestle, BA, hotel chain Novotel, the Royal Bank of Scotland, and Coca-Cola. Known for her evangelical zeal in staff training, her team-building exercises include armchair aerobics, inspirational dancing and fancy dress.

Gober is the Martha Stewart of the customer relations world. She wants the individual to confront the negative aspects of their psychology to bring about change. In other words, she wants bolshie shop assistants to find you that size 20 leopard-skin thong with a good grace. She wants call centre staff to listen deeply and communicate clearly. And never, ever, put you on hold. 'If you have a great product but do not offer a great customer experience to complement it, you are putting your staff and company at risk,' she insists.

Her role model is Gandhi. Her conversation is peppered with buzz phrases such as 'put a smile in your voice' and 'everything I do or say is either a service or disservice to another person'. But don't imagine she's the hippy-dippy type. With her designer suits and immaculately coiffed hair, she resembles a smilier Natasha Kaplinsky. And she doesn't come cheap. M&S is reported to have spent millions of pounds on her services.

Founded in 1979, her firm, Mary Gober International, has its UK headquarters in Camberley, Surrey (there is also an office in New York). She has worked for public and private sector firms in 26 countries from Japan to Estonia, but this is the first time she has been asked to apply her approach to a police force.

After analysing tape recordings of 999 calls at West Mercia, she will be encouraging staff to banish negative phrases and replace them with a 'can-do attitude'. Her recommendations include telling switchboard operators handling routine calls to say 'welcome', give their names and ask how they can help.

In a world where you can spend days being redirected by voice mail without speaking to a single human being, Gober understands the personal touch is everything. 'The telephonist or counter person has to read the conversation and re-act to the customer's mood.'

For a country dependent on its service sector, Britain is still appalling at satisfying customers' needs. According to Will Hutton, executive director of The Work Foundation and an Observer columnist: 'Every queue, every undertrained, disaffected assistant, every poorly designed process - all are the result of treating customer service as a commodity to be produced at the lowest cost by the most sweated workers.' No wonder employers are turning to Gober.

When Marks & Spencer was faced with rising staff turnover, chief executive Stuart Rose brought her in to rally the troops in an attention-grabbing way. She organised three-day, team-building exercises, involving 5,000 staff at a time. Many emerged claiming it had changed their lives, and, yes, sales have gone up.

Each store was vying to display team spirit, whether expressed in dress, flags or mascots. Some, such as Trafford, turned out dressed as navvies. Others, like Reading, had a neat line in natty red T-shirts; Newcastle turned up in their football team's black and white strip. Others were even more outrageous, wearing fancy wigs, bunny ears, arriving with national flags or cuddly toys, from puppies to Welsh sheep

Union leaders, however, branded the project 'all fur coat and no knickers' and claimed it was a waste of £10 million.

Though Gober espouses openness in the workplace, she is surprisingly reticent about herself. She turns down most interview requests and ruthlessly controls her image. 'I don't want to be photographed with my mouth open - it can look so undignified,' she told one journalist. 'Control is everything.'

She was born in Chicago and studied psychology, social work, communication and theatre at Kansas University. She held a faculty position at the University of Illinois before moving to Saudi Arabia, where she worked for Arabian American Oil Company (the world's largest), organising seminars on interpersonal skills. In 1979 she set up her own business as an 'International Human Resource Development Consultant'. Five years ago she moved to the UK.

Her only known vice is a weakness for designer clothes. 'I don't shop that much in the UK,' she revealed in a rare interview. 'I've put together over the years a professional wardrobe. My favourite designer is St John, in California. I've collected many of their pieces, and when they make a skirt it's still the same colour as previous seasons', so it matches. They've got consistency.'

Her stamina is formidable. In addition to her consultancy work, her company offers training seminars for the public (you, too, can attend The Art of Giving Quality Service, £695+VAT), books and videos - all of which present the 'Gober Method' step-by-step system for dealing with customers, colleagues, friends and family that 'keeps you out of the soup'.

Much of Gober's advice builds on neurolingustic programming and the new 'science' of happiness. Even in situations where there's no control over events, she argues, you can still choose your reaction. Constantly pleading powerlessness ('it's out of my hands', 'that's company policy') turns customer service staff into victims, unfulfilled in their work and providing poor service.

Rather grandly, she sees herself as an artist. 'If you were to walk into a museum, you would instantly recognise a piece of work by Monet. I want my work to be the same, so that when people walk into an organisation where I have trained the staff, people in the know will instantly recognise the Gober technique being put into practice.'

A typical Gober training days starts with psychological self-assessment of each of the staff - whether they are 'fun to be around' or 'brave and determined in stressful situations'. This is followed by the bad points - whether they have a 'don't-care attitude' or are 'moody and negative'. Successful salespeople should stay in the black 'can do' positive circle, Gober advises, and avoid the red circle of apathy and indecision. At the end of the day each worker leaves with a list of reminders of how to give good service: a dollar bill with the phrase 'Don't pass the buck - take ownership and responsibility', a gold starfish and an ace of spades playing card ('the ace up your sleeve to give the best customer service'). They are also given a white plastic card reminding them of the key slogans of the day, which they can keep in their top pocket.

Even charities and housing associations are succumbing to Gober's charms. According to Sally Jacobson, group human resources director of London and Quadrant Housing Association: 'We decided to send a few people on a course to see what it was like and soon decided to send everybody from the organisation. The most diehard managers were the most reluctant to go, but they came back completely won over.'

But the strongest recommendation comes from Paul Nolan, head of HSS Services, the hire group that supplies everything from carpet cleaners to mechanical diggers. He told one journalist: 'We were really impressed with Mary Gober - she spent two days researching our business and was prepared to get right down to it, by putting on a boiler suit and driving a digger to get a feel for our work.'

Gober is, of course, not the only charismatic management consultant offering such services. In recent years, an industry has sprung up across the corporate world, using flamboyant stunts from fire-walking to giving out dollar bills. 'Some is part bullshit, and some a response to a real secular change in taste,' says Hutton. 'Employers do need retail-facing staff to take customers' individuals needs and wants much more seriously, and these people are stepping into that breach and offering this kind of motivation. But how enduring the techniques will be, whether some will turn out to be salesmen selling snake oil, I don't know. It's difficult to change a corporate culture. Organisations need to change the way they set targets, they way they pay people, all that stuff.'

David Hencke, one of the few journalists to penetrate a Gober M&S session, told me: 'It sounded semi-evangelical to me. It definitely appeals to these human resources directors that we've all got now who think you don't need unions and you don't need to consult staff, you can just have an inspiring session and they will change.'

Other critics say her methods are a colossally expensive short-term fix. Of course, everyone likes a great day out of the office and a free lunch. But are fancy dress and inspirational dancing really the way to establish a long-term dialogue with staff?

According to workplace expert Jessica Pryce Jones, of the consultancy I-Opener, the most important factor is not what staff come out of their rah-rah sessions enthusing about, but what happens after the event. 'Motivation needs to be there when you have low morale in a company, when people aren't working together well. Aren't we really talking about happiness here?' And she's thoughtful about boundaries: can staff really be expected to cater to customers' every whim? 'I do believe in the word service - I'm not sure if I believe in the word servant.'

'The criticism is that people are enthused and then they go back to work and it wears off,' says Hencke, 'which is rather good news for Mary Gober because she can continually repeat her seminars. No wonder she's making a fortune.'

Mary Gober

Job: Head of Mary Gober International, established in 1979 in New York state

Job description: Customer service culture development

Books: The Art of Giving Quality, Is Your Organisation Customer-focused?, Strategies for Building a Customer-focused Organisation